2021/05/31 by Chethan Krishnan, Roya Mohayaee, Eoin Ó Colgáin +2 · 1 citation
Physics and Astronomy · #astro-ph.CO #gr-qc #hep-ph #hep-th
paper · pdf · doi:10.1088/1361-6382/ac1a81
published as 2021 Class. Quantum Grav. 38 184001 · v1 10 pages, comments welcome, especially on appendix D & Figure 4; v2, typos corrected, Figure 4 improved, observations strengthened; v3 references added, matches version published as invited contribution to CQG "Focus Issue on the Hubble Constant Tension"
arxiv created 2021/08/24 · arxiv updated 2021/08/25
The tension between early and late Universe probes of the Hubble constant has motivated various new FLRW cosmologies. Here, we reanalyse the Hubble tension with a recent age of the Universe constraint. This allows us to restrict attention to matter and a dark energy sector that we treat without assuming a specific model. Assuming analyticity of the Hubble parameter H(z), and a generic low redshift modification to flat ΛCDM, we find that low redshift data (z \lesssim 2.5) and well-motivated priors only permit a dark energy sector close to the cosmological constant Λ. This restriction rules out late Universe modifications within FLRW. We show that early Universe physics that alters the sound horizon can yield an upper limit of H0 ∼ 71 ± 1 km/s/Mpc. Since various local determinations may be converging to H0 ∼ 73 km/s/Mpc, a breakdown of the FLRW framework is a plausible resolution. We outline how future data, in particular strongly lensed quasar data, could also provide further confirmations of such a resolution.